Indiana University-Purdue University Indianapolis (IUPUI) / The relationship between positive urgency, a personality trait reflecting rash action during extreme positive emotional states, and risk-taking has previously been experimentally examined. However, how positive urgency is related to risk-taking while under the acute influence of alcohol has not been examined. The overarching goal of this dissertation was to generate behavioral evidence concerning how the interaction between positive urgency and alcohol consumption influences risk-taking via changes in emotional arousal. In this study, 59 community dwelling adults (mean age = 29.45 (SD = 10.96), 32.2% women, 78% White) completed mood induction procedures (positive or neutral) while consuming a beverage (alcohol or placebo) and then completed the Balloon Analogue Risk Task (BART) as a measure of risk-taking. The positive mood induction was effective in inducing high arousal positive emotions. Overall, study hypotheses were not supported; however, because of low power, effect sizes and patterns of relationship are reported. The relationship between positive urgency and risk-taking was positive and small in the positive mood condition but negative and small in the neutral mood condition. The alcohol group and the placebo group showed similar patterns of risk-taking that are positive and small. Finally, the relationship between positive urgency changes in emotional arousal was positive and small only in the positive/alcohol condition; however, there was no relationship between changes in emotional arousal and risk-taking. These findings suggest that, while changes in emotional arousal may result from a combination of positive urgency and alcohol consumption, it may not be a focal mechanism that explains the relationship between positive urgency and risk-taking. Further, positive urgency is a risk factor whether or not alcohol consumption is present. Although the small sample size limited the power to test the hypotheses, the effect size estimates obtained in this study provide preliminary data for a more properly powered future study. The pattern of findings suggests the viability of further developing the current positive mood induction to establish a lab-based paradigm for positive urgency and the use of a different experimental risk-taking task to examine positive emotion-based risk-taking.

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Objective: Alcohol use disorder (AUD) remains a leading cause of worldwide mortality and morbidity. The development of neuroanatomical biomarkers offers the potential of novel clinical indicators to guide prevention, early diagnosis, and treatment. Methods: In 76 participants with DSM-5 diagnosed AUD (Mage = 35.75; 51.3% female) and 79 controls (Mage = 34.71; 59.5% female), we utilized magnetic resonance imaging (MRI) to investigate four novel measures: hippocampal and amygdalar subregion volumes, sulcal morphology (SM), and fractal dimensionality (FD). MRI processing, segmentation, and SM and FD quantification were completed using FreeSurfer v6.0 and v7.0, and MATLAB toolboxes, respectively. A significance value of p < .05 was employed for analysis and sex, age, and intracranial volume were included as covariates. Results: Volumes of the right presubiculum, subiculum, and molecular layer head; left lateral and accessory basal nuclei; and corticoamygdaloid transition area were significantly lower in AUD participants relative to healthy controls. Widths of the left occipito-temporal, right middle occipital and lunate, and right marginal part of the cingulate sulci and depth of the post-central sulci were significantly increased in AUD participants relative to controls. Finally, decreased left caudate, left thalamus, right putamen and right pallidum FD and greater inferior lateral and third ventricle FD were observed in AUD participants relative to controls. Each novel measure’s reliability was assessed using test-retest data from the Human Connectome Project and indicated high reliability with median intraclass correlations of .93, .91, .88, and .93 for the hippocampal subfields, amygdalar nuclei, SM, and FD, respectively. Conclusion: These results indicate selectively decreased hippocampal and amygdala subregion volume, increased sulcal depth and width, and differences in FD as promising neuroanatomical biomarkers for AUD. / Thesis / Master of Health Sciences (MSc)

The upcoming Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) will change how Alcohol Use Disorder (AUD) is characterized by going from a twoactor hierarchical model to a unidimensional disorder. In addition, the number of criteria needed are being reduced—which may increase AUD prevalence rates. The present study examines how these changes will impact college students as compared to their non-college attending peers. Participants were asked to complete questionnaires about their alcohol use and what criteria they meet, a daily functioning questionnaire, and a measure to determine their willingness to engage in risky behaviors. Results indicate that college students will show a disproportionate increase in diagnoses, even though college students who meet criteria show no significant differences in functional impairment compared to students who do not meet criteria. These results suggest that the new criteria may not be a good indicator of AUD presence for college students.

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This study investigates the relationships between planning strategies on how to avoid future DWI arrest and actual DWI recidivism for a group of problem and non-problem drinkers. A sample of 75 individuals who were arrested for DWI and completed a DWI training program in 1987 was gathered.

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A significant consequence of alcohol use disorders (AUDs) is hippocampal neurodegeneration. The hippocampus is responsible for learning and memory, and neurodegeneration in this brain region has been shown to result in cognitive deficits. Interestingly, some alcoholics demonstrate improvements in hippocampus-dependent functions, potentially due the phenomenon termed adult neurogenesis. Adult neurogenesis, the process by which neural stem cells (NSCs) proliferate, differentiate into neurons, migrate into the granule cell layer, and survive, occurs in two brain regions; however, this study examines only neurogenesis occurring in the subgranular zone of the hippocampal dentate gyrus. Four-day binge ethanol exposure in an animal model causes a decrease in neurogenesis during intoxication; however, there is a reactive increase in cell proliferation on day seven of abstinence. The purpose of this study was to determine the timing of increased cell proliferation. Furthermore, most alcoholics also smoke tobacco, and nicotine, the addictive component of tobacco, has also been shown to affect hippocampal neurogenesis. As many people initiate alcohol and tobacco use during adolescence, the second experiment herein examined the effect of nicotine coadministration on alcohol-induced reactive hippocampal cell proliferation.

published_or_final_version / Community Medicine / Master / Master of Public Health